DESCRIPTION The skid control ECU (brake actuator assembly) measures the speed of each wheel by receiving signals from each speed sensor.
These signals are used for recognizing that all four wheels are operating properly.
Therefore, signals from all wheels must be equal. |
DTC No. | Detection Item |
DTC Detection Condition | Trouble Area | |
C1237 | Speed Sensor Rotor Faulty |
Any of the following is detected:
- Discrepancy among four wheel speed sensor output.
- Abnormal pulse signals from 3 or more sensors.
|
- Tire and wheel size
- Tire deformation
- Speed sensor rotor
- Speed sensor
- Speed sensor circuit
- Skid control ECU (brake actuator assembly)
| WIRING DIAGRAM
Refer to DTCs C1330, C1331, C1332, C1333, C1464, C1465, C1466 and C1467.
Click here  CAUTION / NOTICE / HINT
NOTICE: When
replacing the skid control ECU (brake actuator assembly), perform
system variant learning and acceleration sensor zero point calibration. Click here
HINT: When
C1330, C1331, C1332, C1333, C1464, C1465, C1466 and/or C1467 is output
together with C1237, inspect and repair the trouble areas indicated by
C1330, C1331, C1332, C1333, C1464, C1465, C1466 and/or C1467 first. Click here
PROCEDURE
(a) Check that the DTC is output.
Click here
|
Result | Proceed to | |
C1237 and C1330, C1331, C1332, C1333, 1464, C1465, C1466, C1467 are output simultaneously |
A | | C1237 is output |
B |
| A |
 | GO TO DTCS (C1330, C1331, C1332, C1333, 1464, C1465, C1466 and/or C1467) |
|
B |
 | |
(a) Check the size and condition of all four tires.
Click here HINT: The DTC is output when tire deformation or a difference in tire size is detected.
OK: The diameter and tire pressure of all four tires are the same.
| NG |
| REPLACE TIRES SO THAT ALL FOUR TIRES ARE THE SAME SIZE |
|
OK | |
| |
| 3. |
READ VALUE USING TECHSTREAM (SPEED SENSOR) |
(a) Connect the Techstream to the DLC3. (b) Start the engine. (c) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List. ABS/VSC/TRAC |
Tester Display | Measurement Item |
Range | Normal Condition |
Diagnostic Note | |
FR Wheel Speed | Front wheel speed sensor RH reading |
Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph) |
Vehicle stopped: 0 km/h (0 mph) |
When driving at constant speed: No large fluctuations | |
FL Wheel Speed | Front wheel speed sensor LH reading |
Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph) |
Vehicle stopped: 0 km/h (0 mph) |
When driving at constant speed: No large fluctuations | |
RR Wheel Speed | Rear wheel speed sensor RH reading |
Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph) |
Vehicle stopped: 0 km/h (0 mph) |
When driving at constant speed: No large fluctuations | |
RL Wheel Speed | Rear wheel speed sensor LH reading |
Min.: 0 km/h (0 mph), Max.: 326 km/h (203 mph) |
Vehicle stopped: 0 km/h (0 mph) |
When driving at constant speed: No large fluctuations |
(d) Check the speed sensor output value. OK: The output value changes in accordance with the vehicle speed.
|
Result | Proceed to | |
OK | A | |
NG (The output value for 1 front speed sensor does not change in accordance with the vehicle speed) |
B | | NG (The output value for 1 rear speed sensor does not change in accordance with the vehicle speed) |
C | | NG (The output value of 2 or more sensors does not change in accordance with the vehicle speed) |
D |
| B |
| GO TO STEP 5 |
| C |
| GO TO STEP 14 |
| D |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
|
A | |
| |
| 4. |
PERFORM TEST MODE INSPECTION (SIGNAL CHECK) |
(a) Turn the ignition switch off. (b) Enter the following menus: Chassis / ABS/VSC/TRAC / Utility / Signal Check.
Click here (c) Perform the sensor check using Test Mode (Signal Check) Procedure.
Click here OK: All Test Mode (Signal Check) inspection items change from incomplete to complete.
|
Result | Proceed to | |
OK | A | |
NG (The Test Mode (Signal Check) inspection item for 1 front speed sensor does not change from incomplete to complete) |
B | | NG (The Test Mode (Signal Check) inspection item for 1 rear speed sensor does not change from incomplete to complete) |
C | | NG (The Test Mode (Signal Check) inspection item for 2 or more sensors does not change from incomplete to complete) |
D |
| A |
| USE SIMULATION METHOD TO CHECK |
| B |
| GO TO STEP 5 |
| C |
| GO TO STEP 14 |
| D |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| 5. |
CHECK FRONT SPEED SENSOR INSTALLATION |
| (a) Turn the ignition switch off. |
 |
|
*a | Normal | |
*b | Abnormal | |
*c | Clearance | | |
(b) Check the speed sensor installation. Click here
OK: There is no clearance between the sensor and the front steering knuckle.
The installation bolt is tightened properly.
| NG |
| REINSTALL OR REPLACE FRONT SPEED SENSOR |
|
OK | |
| |
| 6. |
CHECK FRONT SPEED SENSOR (CHECK FOR FOREIGN MATTER) |
(a) Remove the front speed sensor. Click here
(b) Check the front speed sensor tip.
OK: The sensor tip is free of scratches, oil, and foreign matter.
NOTICE:
- If there is oil or foreign matter on the speed sensor, clean the speed sensor.
- If the speed sensor is damaged, replace the speed sensor with a new one.
- Check the speed sensor signal after cleaning or replacement.
Click here
| NG |
| CLEAN OR REPLACE FRONT SPEED SENSOR |
|
OK | |
| |
| 7. |
INSPECT BRAKE ACTUATOR ASSEMBLY (POWER SOURCE CIRCUIT) |
| (a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. |
 |
|
*A | for RH | |
*B | for LH | |
*a | Front view of wire harness connector
(to Front Speed Sensor) | | |
(b) Disconnect the b1 or b2 front speed sensor connector. (c) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (d) Turn the ignition switch to ON.
(e) Measure the voltage according to the value(s) in the table below. Standard Voltage: for RH |
Tester Connection | Condition |
Specified Condition | |
b1-2 - Body ground | Ignition switch ON |
5.5 to 14 V | for LH |
Tester Connection | Condition |
Specified Condition | |
b2-2 - Body ground | Ignition switch ON |
5.5 to 14 V |
| NG |
| GO TO STEP 12 |
|
OK | |
| |
| 8. |
INSPECT BRAKE ACTUATOR ASSEMBLY (GROUND CIRCUIT) |
| (a) Measure the voltage according to the value(s) in the table below.
Standard Voltage: for RH |
Tester Connection | Condition |
Specified Condition | |
b1-2 - b1-1 | Ignition switch ON |
5.5 to 14 V | for LH |
Tester Connection | Condition |
Specified Condition | |
b2-2 - b2-1 | Ignition switch ON |
5.5 to 14 V | | |
|
|
*A | for RH | |
*B | for LH | |
*a | Front view of wire harness connector
(to Front Speed Sensor) | | |
| NG |
| GO TO STEP 10 |
|
OK | |
| |
| 9. |
CHECK FRONT SPEED SENSOR ROTOR (CHECK FOR FOREIGN MATTER) |
(a) Remove the front speed sensor rotor (front axle with ABS rotor bearing assembly).
Click here (b) Check the speed sensor rotor.
OK: The rotor is free of scratches, oil, and foreign matter. NOTICE:
Check the speed sensor signal after cleaning or replacement. Click here
HINT:
- The front speed sensor rotor is incorporated into the front axle with ABS rotor bearing assembly.
- If the front speed sensor rotor needs to be replaced, replace it together with the front axle with ABS rotor bearing assembly.
|
Result | Proceed to | |
OK | A | |
NG (The speed sensor rotor is damaged) |
B | | NG (There is oil or foreign matter on the speed sensor rotor) |
C |
| A |
| REPLACE FRONT SPEED SENSOR |
| B |
| REPLACE FRONT AXLE WITH ABS ROTOR BEARING ASSEMBLY |
| C |
| CLEAN FRONT SPEED SENSOR ROTOR |
| 10. |
INSPECT SKID CONTROL SENSOR WIRE | (a) Turn the ignition switch off.
|
*A | for RH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) |
|
*A | for LH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) | (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the Ab2 or Ab1 skid control sensor wire.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH |
Tester Connection | Condition |
Specified Condition | |
b1-1 - Ab2-1 | Always |
Below 1 Ω | |
b1-1 - Ab2-2 | Always |
10 kΩ or higher | |
b1-1 or Ab2-1 - Body ground |
Always | 10 kΩ or higher | for LH |
Tester Connection | Condition |
Specified Condition | |
b2-1 - Ab1-1 | Always |
Below 1 Ω | |
b2-1 - Ab1-2 | Always |
10 kΩ or higher | |
b2-1 or Ab1-1 - Body ground |
Always | 10 kΩ or higher |
NOTICE: Check the speed sensor signal after replacement. Click here
| NG | |
REPLACE SKID CONTROL SENSOR WIRE |
|
OK | |
| |
| 11. |
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE) |
(a) Turn the ignition switch off. (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the A57 skid control ECU (brake actuator assembly) connector.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH: |
Tester Connection | Condition |
Specified Condition | |
A57-26 (FR-) - Ab2-1 |
Always | Below 1 Ω | |
A57-26 (FR-) or Ab2-1 - Body ground |
Always | 10 kΩ or higher | for LH: |
Tester Connection | Condition |
Specified Condition | |
A57-37 (FL-) - Ab1-1 |
Always | Below 1 Ω | |
A57-37 (FL-) or Ab1-1 - Body ground |
Always | 10 kΩ or higher |
| OK |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
| 12. |
INSPECT SKID CONTROL SENSOR WIRE | (a) Turn the ignition switch off.
|
*A | for RH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) |
|
*A | for LH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) | (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the Ab2 or Ab1 skid control sensor wire.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH |
Tester Connection | Condition |
Specified Condition | |
b1-2 - Ab2-2 | Always |
Below 1 Ω | |
b1-2 - Ab2-1 | Always |
10 kΩ or higher | |
b1-2 or Ab2-2 - Body ground |
Always | 10 kΩ or higher | for LH |
Tester Connection | Condition |
Specified Condition | |
b2-2 - Ab1-2 | Always |
Below 1 Ω | |
b2-2 - Ab1-1 | Always |
10 kΩ or higher | |
b2-2 or Ab1-2 - Body ground |
Always | 10 kΩ or higher |
NOTICE: Check the speed sensor signal after replacement. Click here
| NG | |
REPLACE SKID CONTROL SENSOR WIRE |
|
OK | |
| |
| 13. |
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE) |
(a) Turn the ignition switch off. (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the A57 skid control ECU (brake actuator assembly) connector.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH: |
Tester Connection | Condition |
Specified Condition | |
A57-27 (FR+) - Ab2-2 |
Always | Below 1 Ω | |
A57-27 (FR+) or Ab2-2 - Body ground |
Always | 10 kΩ or higher | for LH: |
Tester Connection | Condition |
Specified Condition | |
A57-36 (FL+) - Ab1-2 |
Always | Below 1 Ω | |
A57-36 (FL+) or Ab1-2 - Body ground |
Always | 10 kΩ or higher |
| OK |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR |
| 14. |
CHECK REAR SPEED SENSOR INSTALLATION |
| (a) Turn the ignition switch off. | |
|
|
*a | Normal | |
*b | Abnormal | |
*c | Clearance | | |
(b) Check the speed sensor installation. Click here
OK: There is no clearance between the sensor and the rear axle carrier.
The installation bolt is tightened properly.
| NG |
| REINSTALL OR REPLACE REAR SPEED SENSOR |
|
OK | |
| |
| 15. |
CHECK REAR SPEED SENSOR (CHECK FOR FOREIGN MATTER) |
(a) Remove the rear speed sensor. Click here
(b) Check the rear speed sensor tip.
OK: The sensor tip is free of scratches, oil, and foreign matter.
NOTICE:
- If there is oil or foreign matter on the speed sensor, clean the speed sensor.
- If the speed sensor is damaged, replace the speed sensor with a new one.
- Check the speed sensor signal after cleaning or replacement.
Click here
| NG |
| CLEAN OR REPLACE FRONT SPEED SENSOR |
|
OK | |
| |
| 16. |
INSPECT BRAKE ACTUATOR ASSEMBLY (POWER SOURCE CIRCUIT) |
| (a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. |
 |
|
*A | for RH | |
*B | for LH | |
*a | Front view of wire harness connector
(to Rear Speed Sensor) | | |
(b) Disconnect the b3 or b4 rear speed sensor connector. (c) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (d) Turn the ignition switch to ON.
(e) Measure the voltage according to the value(s) in the table below. Standard Voltage: for RH |
Tester Connection | Condition |
Specified Condition | |
b3-2 - Body ground | Ignition switch ON |
5.5 to 14 V | for LH |
Tester Connection | Condition |
Specified Condition | |
b4-2 - Body ground | Ignition switch ON |
5.5 to 14 V |
| NG |
| GO TO STEP 21 |
|
OK | |
| |
| 17. |
INSPECT BRAKE ACTUATOR ASSEMBLY (GROUND CIRCUIT) |
| (a) Measure the voltage according to the value(s) in the table below.
Standard Voltage: for RH |
Tester Connection | Condition |
Specified Condition | |
b3-2 - b3-1 | Ignition switch ON |
5.5 to 14 V | for LH |
Tester Connection | Condition |
Specified Condition | |
b4-2 - b4-1 | Ignition switch ON |
5.5 to 14 V | | |
|
|
*A | for RH | |
*B | for LH | |
*a | Front view of wire harness connector
(to Rear Speed Sensor) | | |
| NG |
| GO TO STEP 19 |
|
OK | |
| |
| 18. |
CHECK REAR SPEED SENSOR ROTOR (CHECK FOR FOREIGN MATTER) |
(a) Remove the rear speed sensor rotor (rear axle hub and bearing assembly).
Click here Click here (b) Check the speed sensor rotor.
OK: The rotor is free of scratches, oil, and foreign matter. NOTICE:
Check the speed sensor signal after cleaning or replacement. Click here
HINT:
- The rear speed sensor rotor is incorporated into the rear axle hub and bearing assembly.
- If the rear speed sensor rotor needs to be replaced, replace it together with the rear axle hub and bearing assembly.
|
Result | Proceed to | |
OK | A | |
NG (The speed sensor rotor is damaged) |
B | | NG (There is oil or foreign matter on the speed sensor rotor) |
C |
| A |
| REPLACE REAR SPEED SENSOR |
| B |
| REPLACE REAR AXLE HUB AND BEARING ASSEMBLY |
| C |
| CLEAN REAR SPEED SENSOR ROTOR |
| 19. |
INSPECT SKID CONTROL SENSOR WIRE | (a) Turn the ignition switch off.
|
*A | for RH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) |
|
*A | for LH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) | (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the Rb1 skid control sensor wire.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH |
Tester Connection | Condition |
Specified Condition | |
b3-1 - Rb1-3 | Always |
Below 1 Ω | |
b3-1 - Rb1-4 | Always |
10 kΩ or higher | |
b3-1 - Rb1-2 | Always |
10 kΩ or higher | |
b3-1 - Rb1-1 | Always |
10 kΩ or higher | |
b3-1 or Rb1-1 - Body ground |
Always | 10 kΩ or higher | for LH |
Tester Connection | Condition |
Specified Condition | |
b4-1 - Rb1-1 | Always |
Below 1 Ω | |
b4-1 - Rb1-2 | Always |
10 kΩ or higher | |
b4-1 - Rb1-3 | Always |
10 kΩ or higher | |
b4-1 - Rb1-4 | Always |
10 kΩ or higher | |
b4-1 or Rb1-1 - Body ground |
Always | 10 kΩ or higher |
NOTICE: Check the speed sensor signal after replacement. Click here
| NG | |
REPLACE SKID CONTROL SENSOR WIRE |
|
OK | |
| |
| 20. |
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE) |
(a) Turn the ignition switch off. (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the A57 skid control ECU (brake actuator assembly) connector.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH: |
Tester Connection | Condition |
Specified Condition | |
A57-33 (RR-) - Rb1-3 |
Always | Below 1 Ω | |
A57-33 (RR-) or Rb1-3 - Body ground |
Always | 10 kΩ or higher | for LH: |
Tester Connection | Condition |
Specified Condition | |
A57-30 (RL-) - Rb1-1 |
Always | Below 1 Ω | |
A57-30 (RL-) or Rb1-1 - Body ground |
Always | 10 kΩ or higher |
| OK |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| NG |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| 21. |
INSPECT SKID CONTROL SENSOR WIRE | (a) Turn the ignition switch off.
|
*A | for RH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) |
|
*A | for LH | |
*a | Front view of skid control sensor wire | |
*b | Front view of wire harness connector
(to Sensor Side Connector) | |
*c | Front view of wire harness connector
(to Vehicle Side Connector) | (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the Rb1 skid control sensor wire.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH |
Tester Connection | Condition |
Specified Condition | |
b3-2 - Rb1-4 | Always |
Below 1 Ω | |
b3-2 - Rb1-3 | Always |
10 kΩ or higher | |
b3-2 - Rb1-2 | Always |
10 kΩ or higher | |
b3-2 - Rb1-2 | Always |
10 kΩ or higher | |
b3-2 or Rb1-2 - Body ground |
Always | 10 kΩ or higher | for LH |
Tester Connection | Condition |
Specified Condition | |
b4-2 - Rb1-2 | Always |
Below 1 Ω | |
b4-2 - Rb1-1 | Always |
10 kΩ or higher | |
b4-2 - Rb1-3 | Always |
10 kΩ or higher | |
b4-2 - Rb1-4 | Always |
10 kΩ or higher | |
b4-2 or Rb1-2 - Body ground |
Always | 10 kΩ or higher |
NOTICE: Check the speed sensor signal after replacement. Click here
| NG | |
REPLACE SKID CONTROL SENSOR WIRE |
|
OK | |
| |
| 22. |
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - SKID CONTROL SENSOR WIRE) |
(a) Turn the ignition switch off. (b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.
OK: The connector is securely connected. (c) Disconnect the A57 skid control ECU (brake actuator assembly) connector.
(d) Check both the connector case and the terminals for deformation and corrosion.
OK: No deformation or corrosion. (e) Measure the resistance according to the value(s) in the table below.
Standard Resistance: for RH: |
Tester Connection | Condition |
Specified Condition | |
A57-34 (RR+) - Rb1-4 |
Always | Below 1 Ω | |
A57-34 (RR+) or Rb1-4 - Body ground |
Always | 10 kΩ or higher | for LH: |
Tester Connection | Condition |
Specified Condition | |
A57-29 (RL+) - Rb1-2 |
Always | Below 1 Ω | |
A57-29 (RL+) or Rb1-2 - Body ground |
Always | 10 kΩ or higher |
| OK |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
| NG |
| REPAIR OR REPLACE HARNESS OR CONNECTOR | | 
